Textiles: fiber preparation – Working – Drafting
Reexamination Certificate
2000-02-09
2001-05-29
Calvert, John J. (Department: 3765)
Textiles: fiber preparation
Working
Drafting
C019S258000
Reexamination Certificate
active
06237196
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a top roller used in the drafting apparatus of a spinning frame to draft a sliver.
BACKGROUND OF THE INVENTION
Drafting devices are well known in the art. FIG.
2
and
FIG. 3
show a typical prior art drafting apparatus, and the internal structure of a typical prior art top roller, respectively.
Referring to
FIG. 2
, a drafting apparatus D utilizing a four-point drafting system is comprised of four roller units: a front roller unit
1
(comprising front top roller
1
a
and front bottom roller
1
b
), a second roller unit
2
(comprising second top roller
2
a
provided with apron
2
a
′, and second bottom roller
2
b
provided with apron
2
b
′), a third roller unit
3
(comprising third top roller
3
a
and third bottom roller
3
b
), and a back roller unit
4
(comprising back top roller
4
a
and back bottom roller
4
b
). Front top roller
1
a,
second top roller
2
a,
third top roller
3
a,
and back top roller
4
a
are all held by a bearing or the like arranged inside pivotable arm unit D′.
Downstream of the drafting apparatus D, the spinning frame also includes a spinning unit
5
that spins the drafted sliver into a yarn y using, for example, a vortex air current; and a nip roller
6
a
capable of freely contacting and separating from a delivery roller
6
b
that is continually rotated. The yarn y fed from the spinning unit
5
is nipped between the nip roller
6
a
and the delivery roller
6
b,
and fed downstream to a guide bar
7
, a slack tube
8
and a yarn clearer
9
before being wound into a package
10
rotated by contact with a rotationally driven friction roller
11
.
After being drawn from a sliver container
12
, the sliver s is drafted by the drafting apparatus D, and spun into yarn y by the spinning unit
5
. Next, the spun yarn y is nipped between the nip roller
6
a
and the delivery roller
6
b,
fed past the guide bar
7
, the yarn clearer
9
and so on, and wound into the wound package
10
which is rotated in contact with the friction roller
11
.
In reference to
FIG. 3
, the structure of the conventional prior art top roller T will now be explained. It should be noted that all the top rollers of the drafting apparatus D, including the front top roller
1
a,
second top roller
2
a,
third top roller
3
a,
and back top roller
4
a,
all share the structure shown in the drawing.
The top roller T includes a shaft
13
which is held by a bearing or the like mounted to the pivotable arm unit D′. The shaft
13
is comprised of three main sections: a bearing holding section
13
a
that supports an outside bearing
14
a
on the end of the bearing holding section
13
a,
and an inside bearing
14
b
at the base of the bearing holding section
13
a,
each bearing
14
a,
14
b
having the same diameter and spaced a predetermined distance apart; a central section
13
b
having a diameter slightly larger than the bearing holding section
13
a;
and a base section
13
c
having a diameter slightly larger than the central section
13
b.
A washer
15
having a total diameter slightly larger than the inner diameter of the bearings
14
a,
14
b,
is affixed to the end of the bearing holding section
13
a
with a bolt
16
. The washer
15
prevents the bearings
14
a,
14
b
from dislodging from the bearing holding section
13
a.
A pressure applying spring
17
, arranged between the two bearings
14
a,
14
b,
simultaneously presses the outside bearing
14
a
against the washer
15
, and presses the inside bearing
14
b
against the facing wall
13
d
formed at the juncture of the bearing holding section
13
a
and the central section
13
a
of the shaft
13
. A tubular spacer
18
is formed around the periphery of the pressure applying spring
17
, and arranged between the two bearings
14
a,
14
b.
A roller tube
19
fixedly engages the bearings
14
a,
14
b,
and encloses the central section
13
b
and bearing holding section
13
a
of the shaft
13
, the bearings
14
a,
14
b,
the pressure applying spring
17
, and the spacer
18
.
A C-ring
20
is arranged between a circular groove around the circumference of the spacer
18
and a matching circular groove formed on the inner surface of the roller tube
19
, the C-ring
20
fixedly engaging the spacer
18
with the roller tube
19
, and holding the spacer
18
and the roller tube
19
at a predetermined relative position. A cover
21
is fixedly inserted into the end of the roller tube
19
, and an O-ring
22
is fixedly engaged to a circumferential groove cut into the surface of the central section
13
b
of the shaft
13
help prevent fibrous waste and other matter from entering the inner parts of the top roller T roller.
A top-cot
23
is attached around the circumference of the roller tube
19
and roughly envelopes the area occupied by the bearings
14
a,
14
b.
The top-cot
23
makes contact with the sliver s that is drafted.
The bearing holding section
13
a
of this prior art shaft
13
of the top roller T supports the bearings
14
a,
14
b,
and is formed to a uniform diameter generally between 6 mm and 8 mm. When the bearing holding section
13
a
has a small diameter (6 mm, for example), rigidity is sacrificed, and the bearing holding section
13
a
tends to warp under the heavy load generated by drafting the sliver. Another consequence of using the shaft
13
with a small diameter bearing holding section is that when the top roller T is attached or removed from the drafting apparatus D, large shocks such as might be caused by dropping the top roller T may also cause the shaft
13
to bend. Bends or warps in the shaft
13
lead to drafting abnormalities and flaws in the spun yarn y.
Rigidity of the shaft
13
can be improved when the bearing holding section
13
a
of the shaft
13
is larger (8 mm in diameter, for example), but when the bearing holding section
13
a
is larger, the balls
14
a
′,
14
b
′ in the bearings
14
a,
14
b
must be made smaller, thereby reducing the durability and longevity of the bearings
14
a,
14
b.
In order to solve these problems of the conventional top roller of the drafting apparatus, it is an object of the present invention to provide a top roller that is light, rigid, and durable, and can be attached and removed without concern about damaging the shaft.
SUMMARY OF THE INVENTION
In order to accomplish this object, in the present invention, a top roller arranged on the shaft via a pair of the bearings having the same outer diameter firstly comprises a sectional shaft having a bearing holding section and the base section of which has a larger diameter than the end section, secondly a second bearing is arranged loosely on the end section of the bearing holding section, and thirdly a pressure applying spring is arranged between the two bearings so as to exert pressure against the bearings.
Since, according to the first aspect of the present invention, most of the bearing holding section of the shaft has a large diameter, the shaft is rigid, and reduces the tendency of the shaft to warp under the load of drafting the sliver, or become bent due to large shocks. On the other hand, since the end of the bearing holding section has a small diameter, the bearing that is fit over this section is large enough to support normal balls in the bearing, and improves the longevity of the bearing.
In a second aspect of the present invention, the second bearing is arranged loosely on the end section of the bearing holding section of the shaft, thereby facilitating assembly and disassembly of the top roller, and attachment and removal of the top roller from the drafting apparatus.
In a third aspect of the present invention, a pressure applying spring is arranged between the two bearings, thereby further facilitating assembly and disassembly, and further protecting the bearings against shocks.
REFERENCES:
patent: 1882480 (1932-10-01), Brueshaber
patent: 4116506 (1978-09-01), Moritomo et al.
patent: 4476614 (1984-10-01), Pittroff
patent: 5341569 (1994-08-01), Takamizawa et al.
patent
Armstrong Westerman Hattori McLeland & Naughton LLP
Calvert John J.
Murata Kikai Kabushiki Kaisha
Welch Gary L.
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